He's 'Irish': Mayor Bloomberg knows all too well the foolishness of the St. Patrick's "Irish for today."

Saints preserve us! Has Irish America lost its sense of humor?

Could be.

At least nobody was laughing at Mayor Bloomberg’s off-the-cuff attempt at ethnic drollery, delivered Wednesday to the American Irish Historical Society.

The society is headquartered on Fifth Avenue, close enough to Bloomberg’s personal townhouse so that he sees, as he put it, “a bunch of people that are totally inebriated hanging out the window waving,” as the annual St. Patrick Day’s parade passes.

Not terribly amusing?

Point taken. Maybe Mike should hire away Andy Borowitz’s gag writers.

On the other hand, anybody who’s ever sat through a Friendly Sons of St. Patrick dinner knows that unfunny head-table humor is not unknown to the Irish.

Nonethless, great umbrage was taken.

“The remarks are highly, highly offensive to any Irish person,” said John Dunleavy, chairman of the St. Patrick’s Day Parade committee. “I don’t think he would say a joke like that to any other ethnic group.”

But it was Dunleavy who had this to say back in 2006, when openly gay City Council Speaker Christine Quinn asked to have gay groups finally included in his parade’s line of march:

“If an Israeli group wants to march in New York, do you allow neo-Nazis into their parade?”

It’s useful that he said that — because the comment is a big bay window into his head, where some of St. Patrick’s snakes appear to have taken up residence.

And that’s the thing about the First Amendment, and the whole full-and-free discussion thing: Ugly tropes like Dunleavy’s Nazi allusion fall of their own weight, but along the way democratic consensus is forged.

At a time when it seems that every third drunkery in Manhattan revolves around an Irish theme, shouldn’t the Historical Society worthies consider whether some profound truth might be attached to the mayor’s observation?

Those who deny it would do well to survey the side streets off Fifth Avenue on about 3 p.m. March 17 — if their stomachs are strong enough.

But there will be no such discussion. That would give offense, and the freedom to offend has been all-but-excised from the Constitution, apparently when no one was looking.

America’s campuses are close to wholly offense-free. Question academic orthodoxy on, say, homosexuality, most social issues or US foreign policy, and the hounds of hell will be upon you.

If you are an academic, consider your career to be in grave jeopardy.

Long Island Rep. Pete King has some perfectly reasonable post-Fort Hood/Times Square bombing questions to ask about home-grown Islamic extremism, and he intends to take them before Congress.

But they will give offense to many, so it is fair to wonder whether he will manage to proceed.

Meanwhile, Bloomberg’s Department of Education was delighted to announce on Thursday that a battery of celebrities has signed on to telephone chronically absent high-school students and attempt to cajole them into classrooms.

Nothing wrong with that. But it does raise a judgmental — hence offensive — question: What the hell ever happened to truant officers?

Fact is, you can perform a tonsillectomy on an unwilling kid, but not an education. If he doesn’t want to be in class, it’s time to engage his parents — not Magic Johnson — and to do so as coercively as is necessary.

Some will take offense at this notion because, well, they are easily offended. Too bad about them.

Others use offense as a deflector shield, to protect hidden interests they would prefer not be exposed.

But giving, and taking, offense is integral to the free exchange of ideas — and that is necessary for a vibrant democracy to function.

You know what? Even dumb jokes count.

The Irish in America used to get it. What a pity it would be if we no longer do.